Pregnancy recognition signals in mammals: the roles of interferons and estrogens

Abstract

Reproduction is a highly complex biological process requiring a dialogue between the developing conceptus (embryo-fetus and associated placental membranes) and maternal uterus which must be established during the peri-implantation period for pregnancy recognition signaling and regulation of gene expression by uterine epithelial and stromal cells. The uterus provide a microenvironment in which molecules secreted by uterine epithelia or transported into the uterine lumen represent histotroph or the secretome required for growth and development of the conceptus and receptivity of the uterus to implantation by the conceptus. Pregnancy recognition signaling as related to sustaining the functional lifespan of the corpora lutea (CL) which produce progesterone; the hormone of pregnancy essential for uterine functions that support implantation and placentation required for successful outcomes of pregnancy. It is within the periimplantation period that most embryonic deaths occur in mammals due to deficiencies attributed to uterine functions or failure of the conceptus to develop appropriately, signal pregnancy recognition and/or undergo implantation and placentation. The endocrine status of the pregnant female and her nutritional status are critical for successful establishment and maintenance of pregnancy. The challenge is to understand the complexity of key mechanisms that are characteristic of successful reproduction and to use that knowledge to enhance fertility and reproductive health of animals including nonhuman primates. It is important to translate knowledge gained from studies of animals to address issues of fertility and reproductive health in humans.

Establishment of Bovine Trophoblast Stem Cells

“…1e, f, g ). In ruminants, interferon tau (IFNT) produced by mature trophoblast cells is known as a signal for maternal recognition of pregnancy [14]. By using a luciferase-based IFN stimulatory response element (ISRE) assay [15], we found IFNT production significantly increased upon differentiation of bTSC-LCs and peaked around day 5 ( Fig.…”

Effects of dietary L‐arginine supplementation to early pregnant mares on conceptus diameter—Preliminary findings

“…Several studies have demonstrated a crucial role for NO in enhancing blood flow during ovine pregnancy (Gardner, Powlson, & Giussani, 2001;McCrabb & Harding, 1996). Both NO and polyamines play key roles in angiogenesis, which is a critical event during placental growth and foetal development (Bazer et al, 2017;Wu et al,2004;Wu et al,2013). Formation of the endometrial cups by invasion of the endometrium from chorionic girdle cells marks the beginning of placentation in the horse (Antczak, Mestre, Wilsher, & Allen, 2013).…”

“…Along different growth factors, NO and polyamines are crucial for angiogenesis, embryogenesis, placental and foetal growth, uteroplacental blood flow, and transfer of nutrients from the mother to its foetuses, as well as foetal and placental growth and development. Additionally, arginine activates the mechanistic target of rapamycin (mTOR) cell signalling pathway to stimulate protein synthesis in the placenta, uterus and foetus (Bazer, Wu, & Johnson, ; Wu, Bazer, Cudd, Meininger, & Spencer, ; Wu et al, ). Arginine also has been demonstrated to enhance maternal pregnancy recognition in sheep via increased embryonic interferon tau production (Wang et al, ).…”

Grand Challenge Animal Reproduction-Theriogenology: From the Bench to Application to Animal Production and Reproductive Medicine

“…Another area of advancement in female reproductive biology is the study of maternal recognition of pregnancy (MRP) ( 41 , 42 ). Major advances have been realized in ruminants, shedding light on mechanisms involved in embryo elongation and trophoblast/endometrium cross talk during MRP ( 43 , 44 ).…”